JP5429578B2 - Control device for vehicle drive system - Google Patents

Description

  The present invention relates to a control device for a vehicle drive system including a power transmission device capable of transmitting engine power and motor generator power to a vehicle axle.

  In recent years, a hybrid vehicle equipped with an engine and an MG (motor generator) as a power source of the vehicle has attracted attention because of the social demand for low fuel consumption and low exhaust emissions. In this hybrid vehicle, for example, as described in Patent Document 1 (Japanese Patent Laid-Open No. 9-287490), an MG is disposed on a power transmission path for transmitting engine power to a drive shaft of the vehicle, and the engine A transmission that automatically changes the gear ratio according to the rotation speed of the MG is arranged between the MG and the MG, and the fuel consumption is improved by controlling the engine rotation speed and torque constant. There is.

  Further, as described in Patent Document 2 (Japanese Patent No. 3461652), the engine output shaft, the MG rotation shaft, and the vehicle drive shaft are connected via a planetary gear unit, so that the vehicle is stopped. There is also an engine that can generate electricity by driving the MG with the power of the engine.

JP-A-9-287490 Japanese Patent No. 3,461,652

  However, in the technique of Patent Document 1, since the rotation shaft of the MG and the drive shaft of the vehicle are always connected, the MG cannot be driven by the power of the engine to generate power while the vehicle is stopped. In this case, there is a possibility that the remaining capacity of the battery is reduced and the vehicle cannot travel. As a countermeasure, if a clutch is provided between the MG and the drive shaft, it is necessary to control the clutch with high accuracy when the vehicle starts, so it becomes difficult to ensure the response of the drive torque, and the start performance is reduced. It may get worse.

  Further, in the technique disclosed in Patent Document 2, since the output shaft of the engine, the rotation shaft of the MG, and the drive shaft of the vehicle are connected via the planetary gear unit, the configuration of the power transmission system is complicated or enlarged. There is.

  Therefore, the problem to be solved by the present invention is that of a vehicle drive system that can generate power with MG while the vehicle is stopped and can ensure the start performance of the vehicle while simplifying the configuration of the power transmission device. It is to provide a control device.

  In order to solve the above-mentioned problem, the invention according to claim 1 is directed to engine power, a first motor generator (hereinafter referred to as “first MG”) and a second motor generator (hereinafter referred to as “second MG”). In the control device of the vehicle drive system provided with the power transmission device capable of transmitting the power of the MG) to the axle of the vehicle, the power transmission device includes an engine input shaft for transmitting the engine power, and the first MG. A motor input shaft that transmits power, an output shaft that outputs power for transmission to the axle while receiving power from the second MG, and power from the engine input shaft to the output shaft without passing through the motor input shaft An engine side gear mechanism for transmitting, a motor side gear mechanism for transmitting the power of the motor input shaft to the output shaft without going through the engine input shaft, and power transmission between the engine input shaft and the motor input shaft. Refusal A second clutch that interrupts power transmission between the motor side gear mechanism and the output shaft, and a third clutch that interrupts power transmission between the engine side gear mechanism and the output shaft. And a power transmission control means for determining the engagement / disengagement state of each clutch and the required torque of each MG according to the rotational speed of the axle.

  In this configuration, since the power transmission between the engine and the first MG and the output shaft can be disconnected while the vehicle is stopped, the first MG is driven by the engine power while the vehicle is stopped to generate electric power. be able to. In addition, when the vehicle starts, the output shaft is driven by the power of the second MG to start the vehicle, so that drive torque response can be ensured and start performance can be ensured. Furthermore, since it is not necessary to provide a complicated gear mechanism such as a planetary gear unit in the power transmission device, the configuration of the power transmission device can be simplified and downsized. Moreover, by determining the on / off state of each clutch and the required torque of each MG according to the rotational speed of the axle, it is possible to appropriately control each clutch and each MG according to the rotational speed of the axle.

  According to the second aspect of the present invention, the required torque of the engine is preferably set to a constant value during operation of the engine. In this way, it is possible to maintain the engine torque constant and improve fuel efficiency and reduce exhaust emissions.

  In this case, as in the third aspect, when the rotational speed of the axle is equal to or lower than the predetermined first rotational speed, the first clutch is connected and the second and third clutches are disconnected. In this way, in the low speed region (including when the vehicle is stopped) where the rotational speed of the axle is equal to or lower than the first rotational speed, the power transmission between the engine and the first MG and the output shaft is disconnected. Thus, the first MG can be driven by the power of the engine to generate electric power, and the vehicle can be driven by driving the output shaft with the power of the second MG.

  Further, as in claim 4, it is preferable to set the required torque of the first MG to the same value as the required torque of the engine and set the required torque of the second MG based on the required torque of the output shaft. . In this way, the required torque of the output shaft can be realized by the second MG while maintaining the engine torque constant.

  Further, as in claim 5, when the rotational speed of the axle is higher than the predetermined first rotational speed and equal to or lower than the predetermined second rotational speed, the gear of the engine side gear mechanism and the motor side gear mechanism is Each clutch may be controlled so that the engine power is transmitted to the output shaft via the gear mechanism having the larger ratio. In this way, in the low to medium speed range where the rotational speed of the axle is higher than the first rotational speed and equal to or lower than the second rotational speed, the low gear mechanism (the gear mechanism having the larger gear ratio) is used. Engine power can be transmitted to the output shaft.

  Further, as in the sixth aspect, when the rotational speed of the axle is higher than the predetermined second rotational speed, the gear mechanism having the smaller gear ratio between the engine side gear mechanism and the motor side gear mechanism is used. Each clutch may be controlled to transmit engine power to the output shaft. In this way, in the medium to high speed range where the axle rotational speed is higher than the second rotational speed, the engine power is transmitted to the output shaft via the high gear mechanism (the gear mechanism with the smaller gear ratio). can do.

  Further, as in claim 7, the required power of the MG is calculated based on the target power of the engine determined from the gear ratio of the gear mechanism that transmits the engine power to the output shaft and the required power of the output shaft. It is good to make it. In this way, the required power of MG required to realize the required power of the output shaft during the operation of the engine can be set with high accuracy.

  Further, as in claim 8, it is preferable that the first and third clutches are disconnected and the second clutch is connected while the operation of the engine is stopped. In this way, the output shaft is driven by the power of at least one of the first MG and the second MG to run the vehicle, or the first shaft is driven by the power of the output shaft driven by the power of the axle. Electric power can be generated by driving at least one of the MG and the second MG.

  In this case, as in claim 9, the MG required power may be set to the same value as the required output shaft power. In this way, it is possible to accurately set the required power of the MG necessary for realizing the required power of the output shaft while the engine is stopped.

  Further, as in claim 10, a map of the optimum operating point at which the total loss of the MG is minimized is stored in advance, and the first MG requested torque and the first MG based on the requested MG power are stored using the map. The required torque of MG 2 may be calculated. In this way, the required torque of the first MG and the required torque of the second MG can be set so that the total loss of the MG is minimized.

FIG. 1 is a diagram showing a schematic configuration of a hybrid vehicle drive system in an embodiment of the present invention. FIG. 2 is a diagram for explaining the control of the clutch and MG according to the rotational speed Nd of the axle. FIG. 3 is a diagram conceptually illustrating an example of a map of the MG maximum torque. FIG. 4 is a diagram conceptually illustrating an example of a map of MG loss. FIG. 5 is a diagram conceptually showing an example of a map of the MG optimum operating point. FIG. 6 is a flowchart (part 1) showing the flow of processing of the power transmission control routine. FIG. 7 is a flowchart (part 2) showing the flow of processing of the power transmission control routine.

Hereinafter, an embodiment embodying a mode for carrying out the present invention will be described.
First, a schematic configuration of a hybrid vehicle drive system will be described with reference to FIG.

  The power transmission device 11 mounted on the hybrid vehicle includes an engine 12, a first motor generator (hereinafter referred to as “first MG”) 13, and a second motor generator (hereinafter referred to as “second MG”). ) 14, first engine input shaft 15, damper 16, second engine input shaft 17, motor input shaft 18, engine side drive gear 19 and driven gear 20, motor side drive gear 21 and driven gear 22, first clutch 23 The second clutch 24, the third clutch 25, the output shaft 26, the differential gear 27, and the like are provided, and the power (that is, the drive torque) generated by the engine 12, the first and second MGs 13 and 14 is transmitted to the axle 28. Thus, a driving force is generated in the driving wheel 29.

  The first and second MGs 13 and 14 are connected to a battery 31 (storage battery) via an inverter 30, and the first and second MGs 13 and 14 exchange power with the battery 31 via the inverter 30. ing. The engine 12 is an internal combustion engine, and the first and second MGs 13 and 14 are electric motors that are rotated by the electric power of the battery 31, and the power transmission device 11 (specifically, the motor input shaft 18 for the first MG 13). In the case of the second MG 14, it is also a generator that generates power using the shaft torque transmitted from the output shaft 26) and charges the battery 31.

  Power generated by the engine 12 is input to a first engine input shaft 15 extending from the engine 12. The first engine input shaft 15 functions as a shaft for transmitting power input from the engine 12. A known torsion damper 16 is attached to the end of the first engine input shaft 15 opposite to the engine 12.

  A second engine input shaft 17 is coaxially attached to the first engine input shaft 15 on the opposite side of the damper 16 from the first engine input shaft 15. Therefore, the second engine input shaft 17 transmits the power of the first engine input shaft 15 via the damper 16.

  An engine-side drive gear 19 is attached to the second engine input shaft 17, and the drive gear 19 rotates together with the second engine input shaft 17.

  In addition, the power generated by the first MG 13 is input to the motor input shaft 18 extending from the first MG 13. The motor input shaft 18 functions as a shaft for transmitting power input from the first MG 13.

  A motor-side drive gear 21 is attached to the motor input shaft 18, and the drive gear 21 rotates together with the motor input shaft 18.

  The second engine input shaft 17 and the motor input shaft 18 are arranged in parallel and coaxial with each other. The first clutch 23 is a clutch mechanism that is provided between the second engine input shaft 17 and the motor input shaft 18 and intermittently connects and disconnects the second engine input shaft 17 and the motor input shaft 18. As the first clutch 23, a wet clutch may be employed, or a dry clutch may be employed.

  Also, the power generated by the second MG 14 is input to the output shaft 26 extending from the second MG 14. The output shaft 26 is disposed on the side of the first engine input shaft 15, the second engine input shaft 17, and the motor input shaft 18 in parallel to the input shafts 15, 17, 18, and includes a differential gear 27, an axle 28. Power to transmit to etc. is output.

  The engine-side driven gear 20 meshes with the drive gear 19 and is rotatably supported by the output shaft 26. The third clutch 25 is a clutch mechanism that is attached to the output shaft 26 and that intermittently connects the output shaft 26 and the driven gear 20. As the third clutch 25, a wet clutch may be employed, a dry clutch may be employed, or a meshing clutch such as a synchro mechanism may be employed.

  The motor-side driven gear 22 meshes with the drive gear 21 and is rotatably supported by the output shaft 26. The second clutch 24 is a clutch mechanism that is attached to the output shaft 26 and that intermittently connects the output shaft 26 and the driven gear 22. As the second clutch 24, a wet clutch may be employed, a dry clutch may be employed, or a meshing clutch such as a synchro mechanism may be employed.

  The power of the output shaft 26 is transmitted to the drive wheels 29 via a final gear and a differential gear 27 and an axle 28 (not shown).

  By connecting the third clutch 25, power is transmitted between the output shaft 26 and the engine-side driven gear 20. Accordingly, power is transmitted between the second engine input shaft 17 and the output shaft 26 (not via the motor input shaft 18) via the engine-side drive gear 19, driven gear 20, and third clutch 25. Conversely, when the third clutch 25 is disengaged, power transmission via the engine-side drive gear 19 and the driven gear 20 is not performed between the second engine input shaft 17 and the output shaft 26. The engine-side drive gear 19 and the driven gear 20 constitute a high gear mechanism 32 (corresponding to an example of an engine-side gear mechanism). The reduction ratio (gear ratio) of the high gear mechanism 32 is smaller than the reduction ratio (gear ratio) of the low gear mechanism 33 described later.

  Further, by connecting the second clutch 24, power transmission is performed between the output shaft 26 and the driven gear 22 on the motor side. Accordingly, power is transmitted between the motor input shaft 18 and the output shaft 26 (not through the engine input shafts 15 and 17) via the motor-side drive gear 21, driven gear 22, and second clutch 24. On the other hand, when the second clutch 24 is disengaged, power transmission between the motor input shaft 18 and the output shaft 26 via the drive gear 21 and the driven gear 22 on the motor side is not performed. The motor-side drive gear 21 and the driven gear 22 constitute a low gear mechanism 33 (corresponding to an example of a motor-side gear mechanism). The reduction ratio (gear ratio) of the low gear mechanism 33 is larger than the reduction ratio (gear ratio) of the high gear mechanism 32.

  In this power transmission device 11, the gear mechanism closer to the engine 12 is the high gear mechanism 32 and the gear mechanism closer to the first MG 13 is the low gear mechanism, both when viewed from the power transmission path and from the arrangement. 33.

  Further, when the first clutch 23 is connected, power is transmitted between the second engine input shaft 17 and the motor input shaft 18 via the first clutch 23, and when the first clutch 23 is disconnected. The power is not transmitted between the second engine input shaft 17 and the motor input shaft 18.

  When the first clutch 23 is connected, power is always transmitted from the position where the drive gear 19 is provided on the second engine input shaft 17 to the position where the drive gear 21 is provided on the motor input shaft 18. Is possible. In other words, no clutch other than the first clutch 23 is interposed in the power transmission path from the position where the engine-side drive gear 19 is provided on the input shafts 15, 17, 18 to the motor-side drive gear 21. As a result, the number of clutches can be reduced as compared with the conventional case, and the power transmission device 11 can be downsized.

  Further, the distance from the engine 12 to the engine-side drive gear 19 is reduced by arranging the first clutch 23 and the engine-side drive gear 19 between the motor-side drive gear 21 and the engine 12. As a result, the resistance against the torsional vibration of the engine input shafts 15 and 17 can be kept high.

  Further, by arranging the first clutch 23 and the motor-side drive gear 21 at a position between the engine-side drive gear 19 and the first MG 13, from the first MG 13 to the motor-side drive gear 21. As a result, the resistance against torsional vibration of the motor input shaft 18 can be kept high.

  The ECU 34 (electronic control circuit) is configured mainly with a microcomputer, and based on various physical quantities acquired in the vehicle, the first and second MGs 13 and 14 are driven / not driven, and the first By controlling the connection / disconnection of the first to third clutches 23 to 25, the transmission path and the reduction ratio of the power generated by the engine 12 and the first MG 13 are controlled.

  The ECU 34 includes a vehicle speed detected by a vehicle speed sensor (not shown), an accelerator opening (accelerator operation amount) detected by an accelerator sensor (not shown), and a battery 31 detected by a battery monitoring device (not shown). Various signals such as an SOC (State Of Charge) representing a state of charge and an engine speed detected by a crank angle sensor (not shown) are input.

  The ECU 34 switches connection / disconnection of the first to third clutches 23 to 25 based on these input signals. Specifically, the ECU 34 controls the operation of actuators provided for the clutches 23 to 25 (for example, actuators that generate hydraulic pressure for clutch engagement / disengagement), thereby connecting / disconnecting the clutches 23 to 25. Switch cutting individually.

  By such control of the clutches 23 to 25 by the ECU 34, the power generated by the first MG 13 is transmitted to the driving wheel 29 via the low gear mechanism 33 or to the driving wheel 29 via the high gear mechanism 32. It is also possible to be done. Further, the power generated by the engine 12 can be transmitted to the drive wheels 29 via the low gear mechanism 33 or can be transmitted to the drive wheels 29 via the high gear mechanism 32.

  In this embodiment, the ECU 34 executes a power transmission control routine shown in FIGS. 6 and 7 to be described later, so that the clutches 23 to 25 are in an intermittent state (connected / disconnected) and each MG 13 according to the rotational speed Nd of the axle 28. , 14 is determined as follows.

The first rotational speed N1 and the second rotational speed N2 for determining the region of the rotational speed Nd of the axle 28 are set within the ranges satisfying the following conditions (where N1 <N2).
Nmin / ρl / ρf ≦ N1 ≦ Nmax / ρl / ρf
Nmin / ρh / ρf ≦ N2 ≦ Nmax / ρh / ρf
Here, Nmin is the minimum rotation speed (for example, idle rotation speed) of the engine 12, and Nmax is the maximum rotation speed of the engine 12. Ρl is the gear ratio of the low gear mechanism 33, ρh is the gear ratio of the high gear mechanism 32, and ρf is the final gear ratio.

  During the operation of the engine 12, the required torque Te of the engine 12 is set to a constant value. As a result, the torque of the engine 12 is kept constant, and fuel efficiency improvement and exhaust emission reduction can be realized.

  As shown in FIG. 2A, when the rotational speed Nd of the axle 28 is equal to or lower than the first rotational speed N1 during operation of the engine 12 (when 0 ≦ Nd ≦ N1), the first clutch 23 is engaged. The second and third clutches 24 and 25 are disconnected by connection. As a result, in the low speed region (including when the vehicle is stopped) where the rotational speed Nd of the axle 28 is equal to or lower than the first rotational speed N1, power transmission between the engine 12 and the first MG 13 and the output shaft 26 is disconnected. In this state, the first MG 13 can be driven by the power of the engine 12 to generate power, and the output shaft 26 can be driven by the power of the second MG 14 to drive the vehicle.

  In this case, the required torque Tmg1 of the first MG 13 is set to the same value as the required torque Te of the engine 12, and the required torque Tmg2 of the second MG 14 is set based on the required torque To of the output shaft 26. Thus, the required torque To of the output shaft 26 can be realized by the second MG 14 while maintaining the torque of the engine 12 constant.

  As shown in FIG. 2 (b), when the rotational speed Nd of the axle 28 is higher than the first rotational speed N1 and lower than the second rotational speed N2 during the operation of the engine 12 (in the case of N1 <Nd ≦ N2). ), The clutches 23 to 25 are controlled so that the power of the engine 12 is transmitted to the output shaft 26 via the low gear mechanism 33 (the gear mechanism having the larger gear ratio). Specifically, the first and second clutches 23 and 24 are connected and the third clutch 25 is disconnected. As a result, in the low to medium speed range where the rotational speed Nd of the axle 28 is higher than the first rotational speed N1 and less than or equal to the second rotational speed N2, the power of the engine 12 is transmitted via the low gear mechanism 33 to the output shaft 26. To be able to communicate.

  In this case, based on the target power Pe of the engine 12 determined from the gear ratio ρl of the low gear mechanism 33 and the required power Po of the output shaft 26, the MG required power Pmg (= the required power of the first MG 13 and the second MG 14). (Total value of required power). As a result, the MG required power Pmg necessary for realizing the required power Po of the output shaft 26 in the low to medium speed range during operation of the engine 12 is set with high accuracy. Thereafter, by calculating a required torque Tmg1 of the first MG 13 and a required torque Tmg2 of the second MG 14 based on the MG required power Pmg using a map of the MG optimum operating point described later, the engine 12 is operating. The required torque Tmg1 of the first MG 13 and the request of the second MG 14 so that the total MG loss (= total value of the loss of the first MG 13 and the loss of the second MG 14) is minimized in the low to medium speed range of Set the torque Tmg2.

  As shown in FIG. 2C, when the rotational speed Nd of the axle 28 is higher than the second rotational speed N2 during operation of the engine 12 (when N2 <Nd), the high gear mechanism 32 (gear ratio is The clutches 23 to 25 are controlled so that the power of the engine 12 is transmitted to the output shaft 26 via the smaller gear mechanism. Specifically, the first clutch 23 is disconnected and the second and third clutches 24 and 25 are connected. As a result, the power of the engine 12 can be transmitted to the output shaft 26 via the high gear mechanism 32 in the medium to high speed range where the rotational speed Nd of the axle 28 is higher than the second rotational speed N2.

  In this case, the MG required power Pmg is calculated based on the target power Pe of the engine 12 determined from the gear ratio ρh of the high gear mechanism 32 and the required power Po of the output shaft 26. As a result, the MG required power Pmg necessary for realizing the required power Po of the output shaft 26 in the medium speed to high speed range during operation of the engine 12 is set with high accuracy. Thereafter, by calculating a required torque Tmg1 of the first MG 13 and a required torque Tmg2 of the second MG 14 based on the MG required power Pmg using a map of the MG optimum operating point described later, the engine 12 is operating. The required torque Tmg1 of the first MG 13 and the required torque Tmg2 of the second MG 14 are set so that the MG total loss is minimized in the medium speed to high speed range.

  On the other hand, when the operation of the engine 12 is stopped (when combustion is stopped), the first and third clutches 23 and 25 are disconnected and the second clutch 24 is connected. Thereby, the output shaft 26 is driven by the power of one or both of the first MG 13 and the second MG 14 to drive the vehicle, or the first power is driven by the power of the output shaft 26 driven by the power of the axle 28. One or both of the MG 13 and the second MG 14 are driven so that power can be generated.

  In this case, by setting the MG required power Pmg to the same value as the required power Po of the output shaft 26, the MG required power Pmg required to realize the required power Po of the output shaft 26 while the engine 12 is stopped. Set with high accuracy. Thereafter, the engine 12 is stopped by calculating the required torque Tmg1 of the first MG 13 and the required torque Tmg2 of the second MG 14 based on the MG required power Pmg using a map of the MG optimum operating point described later. The required torque Tmg1 of the first MG 13 and the required torque Tmg2 of the second MG 14 are set so that the total MG loss is minimized.

  Next, a method for creating a map of the MG optimum operating point will be described. The map of the MG optimum operating point is created in advance at the design stage or the manufacturing stage and stored in the ROM of the ECU 34.

[Calculation of MG operation point candidates]
The MG required power Pmg during power running is the maximum torque Tmg1.max (see FIG. 3) of the first MG13, the rotational speed Nmg1 of the first MG13, and the maximum torque Tmg2.max (see FIG. 3) of the second MG14. ) And the rotational speed Nmg2 of the second MG 14 can be expressed by the following equation (1).

Pmg = 2π / 60 × (ρl × η × x × Tmg1.max × Nmg1 / ρl
+ Y × Tmg2.max × Nmg2) (1)
Here, x is the torque load factor of the first MG 13, y is the torque load factor of the second MG 14, and η is the gear efficiency of the low gear mechanism 33.

The maximum required power Pmg1.max of the first MG 13 and the maximum required power Pmg2.max of the second MG 14 can be expressed by the following formulas (2) and (3), respectively.
Pmg1.max = 2π / 60 × Tmg1.max × Nmg1 (2)
Pmg2.max = 2π / 60 × Tmg2.max × Nmg2 (3)

The above (1) can be transformed into the following equation (4) using the relationship between the above equations (2) and (3).
Pmg = η × x × Pmg1.max + y × Pmg2.max (4)

Here, assuming that a (Nmg1) = Pmg1.max (Nmg1) /Pmg2.max (Nmg1), the above equation (4) can be transformed into the following equation (5).
Pmg = η × x × (1 + y / a) × Pmg1.max (5)

The following equation (6) can be obtained by solving the equation (5) for y.
y (x) = − a × x + a × Pmg / (η × Pmg1.max) (6)

On the other hand, the MG required power Pmg at the time of regeneration can be expressed by the following equation (7).
Pmg = 1 / η × x × Pmg1.max + y × Pmg2.max (7)

The following equation (8) can be obtained by solving the equation (7) for y.
y (x) = − a × x + a × η × Pmg / Pmg1.max (8)

[Determination of MG optimum operating point]
For each of x and y that can be taken for the case where the above equation (6) representing the relationship between x and y during power running is used and the case where the above equation (8) representing the relationship between x and y during regeneration is used. The loss Pmg1.loss (x × Tmg1.max, Nmg1) of the first MG13 and the loss Pmg2.loss (y × Tmg2.max, Nmg2) of the second MG14 are used in the MG loss map (see FIG. 4). To calculate. This MG loss map is created based on test data, design data, and the like.

Thereafter, using the loss Pmg1.loss (x × Tmg1.max, Nmg1) of the first MG13 and the loss Pmg2.loss (y × Tmg2.max, Nmg2) of the second MG14, the total MG loss Pmg.loss Is calculated by the following equation.
Pmg.loss = Pmg1.loss (x × Tmg1.max, Nmg1)
+ Pmg2.loss (y x Tmg2.max, Nmg2)

  The torque load factor x of the first MG 13 that minimizes the MG total loss Pmg.loss is calculated as the MG optimum operating point xopt, the MG optimum operating point xopt, the MG required power Pmg, and the rotational speed Nmg1 of the first MG 13 A map (see FIG. 5) of the MG optimum operating point that defines the relationship between the ECU 34 and the ECU 34 is stored in the ROM.

  Hereinafter, processing contents of the power transmission control routine shown in FIGS. 6 and 7 executed by the ECU 34 in this embodiment will be described.

  The power transmission control routine shown in FIG. 6 and FIG. 7 is repeatedly executed at a predetermined cycle during the power-on period of the ECU 34, and serves as power transmission control means in the claims. When this routine is started, first, in step 101, the required torque To of the output shaft 26 is calculated by a map or a mathematical formula based on the accelerator opening detected by the accelerator sensor, the vehicle speed detected by the vehicle speed sensor, and the like.

  Thereafter, the routine proceeds to step 102, where the rotational speed Nd of the axle 28 is calculated based on the vehicle speed detected by the vehicle speed sensor. When the rotational speed Nd of the axle 28 is detected by the vehicle speed sensor, the rotational speed Nd of the axle 28 is read.

Thereafter, the process proceeds to step 103, and the required power Po of the output shaft 26 is calculated by the following equation using the required torque To of the output shaft 26, the rotational speed Nd of the axle 28, and the final gear ratio ρf.
Po = 2π / 60 × To × Nd × ρf

  Thereafter, the routine proceeds to step 104, where it is determined whether or not the engine 12 is in operation. If it is determined that the engine 12 is not in operation (that is, the operation of the engine 12 is stopped), step 105 is performed. Then, after disconnecting the first and third clutches 23, 25, the process proceeds to step 106, where the second clutch 24 is connected. Thereby, the output shaft 26 is driven by the power of one or both of the first MG 13 and the second MG 14 to drive the vehicle, or the first power is driven by the power of the output shaft 26 driven by the power of the axle 28. One or both of the MG 13 and the second MG 14 are driven so that power can be generated.

Thereafter, the routine proceeds to step 107, where the MG required power Pmg is set to the same value as the required power Po of the output shaft 26, so that it is necessary to realize the required power Po of the output shaft 26 while the engine 12 is stopped. Set MG required power Pmg with high accuracy.
Pmg = Po

Thereafter, the process proceeds to step 108, where the maximum torque Tmg1.max of the first MG 13 corresponding to the rotational speed Nmg1 of the first MG 13 is calculated using the map of the MG maximum torque shown in FIG. After calculating the MG optimum operating point xopt corresponding to the MG required power Pmg and the rotation speed Nmg1 of the first MG 13 using the map of the MG optimum operating point shown, the MG optimum operating point xopt and the maximum of the first MG 13 are calculated. Using the torque Tmg1.max, the required torque Tmg1 of the first MG 13 is calculated by the following equation.
Tmg1 = xopt x Tmg1.max

  The MG maximum torque map shown in FIG. 3 is created in advance based on test data, design data, and the like, and is stored in the ROM of the ECU 34. Further, the map of the MG optimum operating point shown in FIG. 5 is created in advance by the method described above and stored in the ROM of the ECU 34.

Thereafter, the routine proceeds to step 109, where the maximum torque Tmg2.max of the second MG 14 corresponding to the rotational speed Nmg2 of the second MG 14 is calculated using the map of the MG maximum torque shown in FIG. The torque load factor y of the second MG 14 is calculated after calculating the torque load factor y of the second MG 14 according to the MG optimum operating point xopt using the above equation (8) at the time of regeneration using the equation (6). And the maximum torque Tmg2.max of the second MG14, the required torque Tmg2 of the second MG14 is calculated by the following equation.
Tmg2 = y x Tmg2.max

  By the processing of these steps 108 and 109, the required torque Tmg1 of the first MG 13 and the required torque Tmg2 of the second MG 14 are set so that the MG total loss is minimized while the operation of the engine 12 is stopped.

On the other hand, if it is determined in step 104 that the engine 12 is in operation, the process proceeds to step 110 where the required torque Te of the engine 12 is set to a constant value so that the torque of the engine 12 is kept constant. This makes it possible to improve fuel efficiency and reduce exhaust emissions.
Te = constant value

  Thereafter, the routine proceeds to step 111, where it is determined whether or not the rotational speed Nd of the axle 28 is equal to or lower than the first rotational speed N1. If it is determined in step 111 that the rotational speed Nd of the axle 28 is equal to or lower than the first rotational speed N1 (0 ≦ Nd ≦ N1), it is a low speed region (including when the vehicle is stopped). In step 112, the second and third clutches 24, 25 are disengaged. Then, the process proceeds to step 113, where the first clutch 23 is connected. Thus, in the low speed range (including when the vehicle is stopped), the power transmission between the engine 12 and the first MG 13 and the output shaft 26 is disconnected, and the first MG 13 is driven by the power of the engine 12. The power can be generated and the output shaft 26 is driven by the power of the second MG 14 so that the vehicle can travel.

Thereafter, the routine proceeds to step 114 where the required torque Tmg1 of the first MG 13 is set to the same value as the required torque Te of the engine 12.
Tmg1 = Te

Thereafter, the routine proceeds to step 115, where the required torque Tmg2 of the second MG 14 is set to the same value as the required torque To of the output shaft 26.
Tmg2 = To
Thus, the required torque To of the output shaft 26 can be realized by the second MG 14 while maintaining the torque of the engine 12 constant.

  On the other hand, if it is determined in step 111 that the rotational speed Nd of the axle 28 is higher than the first rotational speed N1, the routine proceeds to step 116 in FIG. 7, where the rotational speed Nd of the axle 28 is changed to the second rotational speed. It is determined whether the speed is N2 or less.

  In this step 116, when it is determined that the rotational speed Nd of the axle 28 is equal to or lower than the second rotational speed N2 (when N1 <Nd ≦ N2), it is determined to be in the low speed to medium speed range, Proceeding to step 117, the third clutch 25 is disconnected, and then proceeding to step 118, where the first and second clutches 23, 24 are connected. Thus, in the low speed to medium speed range, the power of the engine 12 can be transmitted to the output shaft 26 via the low gear mechanism 33.

Thereafter, the process proceeds to step 119, and the calculation gear ratio ρ used for calculating the target rotational speed Ne of the engine 12 is set to the gear ratio ρl of the low gear mechanism 33 in step 123 described later.
ρ = ρl

  On the other hand, if it is determined in step 116 that the rotational speed Nd of the axle 28 is higher than the second rotational speed N2 (when N2 <Nd), it is determined that the speed is in the medium to high speed range. Proceeding to step 120 and disconnecting the first clutch 23, the process proceeds to step 121, where the second and third clutches 24, 25 are connected. As a result, the power of the engine 12 can be transmitted to the output shaft 26 via the high gear mechanism 32 in the medium speed to high speed range.

Thereafter, the routine proceeds to step 122 where the calculation gear ratio ρ used for calculating the target rotational speed Ne of the engine 12 is set to the gear ratio ρh of the high gear mechanism 32 in step 123 described later.
ρ = ρh

Thereafter, the routine proceeds to step 123, where the target rotational speed Ne of the engine 12 is calculated by the following equation using the calculation gear ratio ρ, the final gear ratio ρf and the rotational speed Nd of the axle 28.
Ne = ρ × ρf × Nd

Thereafter, the routine proceeds to step 124, where the target power Pe of the engine 12 is calculated by the following equation using the required torque Te of the engine 12 and the target rotational speed Ne.
Pe = 2π / 60 × Te × Ne

Thereafter, the routine proceeds to step 125, where the required power Po of the output shaft 26 is realized by calculating the MG required power Pmg by the following equation using the required power Po of the output shaft 26 and the target power Pe of the engine 12. The required MG required power Pmg is set with high accuracy.
Pmg = Po-Pe

Thereafter, the process proceeds to step 126, where the maximum torque Tmg1.max of the first MG 13 corresponding to the rotational speed Nmg1 of the first MG 13 is calculated using the map of the MG maximum torque shown in FIG. After calculating the MG optimum operating point xopt corresponding to the MG required power Pmg and the rotation speed Nmg1 of the first MG 13 using the map of the MG optimum operating point shown, the MG optimum operating point xopt and the maximum of the first MG 13 are calculated. Using the torque Tmg1.max, the required torque Tmg1 of the first MG 13 is calculated by the following equation.
Tmg1 = xopt x Tmg1.max

Thereafter, the process proceeds to step 127, and the maximum torque Tmg2.max of the second MG 14 corresponding to the rotational speed Nmg2 of the second MG 14 is calculated using the map of the MG maximum torque shown in FIG. The torque load factor y of the second MG 14 is calculated after calculating the torque load factor y of the second MG 14 according to the MG optimum operating point xopt using the above equation (8) at the time of regeneration using the equation (6). And the maximum torque Tmg2.max of the second MG14, the required torque Tmg2 of the second MG14 is calculated by the following equation.
Tmg2 = y x Tmg2.max

  By the processing of these steps 126 and 127, the required torque Tmg1 of the first MG 13 and the second MG 14 so that the MG total loss is minimized in the low speed to medium speed region and the medium speed to high speed region during operation of the engine 12. Set the required torque Tmg2.

  In the present embodiment described above, since the power transmission between the engine 12 and the first MG 13 and the output shaft 26 can be disconnected while the vehicle is stopped, the first power is generated by the power of the engine 12 while the vehicle is stopped. The MG 13 can be driven to generate power. Further, when the vehicle starts, the output shaft 26 is driven by the power of the second MG 14 to start the vehicle, so that the drive torque response can be ensured and the start performance can be ensured. Further, since it is not necessary to provide the power transmission device 11 with a complicated gear mechanism such as a planetary gear unit, the configuration of the power transmission device 11 can be simplified and downsized. In addition, the clutch 23 to 25 and the MGs 13 and 14 can be controlled according to the rotational speed of the axle 28 by determining the on / off state of the clutches 23 to 25 and the required torque of the MGs 13 and 14 according to the rotational speed of the axle 28. Can be controlled appropriately.

  DESCRIPTION OF SYMBOLS 11 ... Power transmission device, 12 ... Engine, 13, 14 ... MG, 15, 17 ... Engine input shaft, 18 ... Motor input shaft, 19 ... Drive gear, 20 ... Driven gear, 21 ... Drive gear, 22 ... Driven gear, 23- DESCRIPTION OF SYMBOLS 25 ... Clutch, 26 ... Output shaft, 28 ... Axle, 32 ... High gear mechanism (engine side gear mechanism), 33 ... Low gear mechanism (motor side gear mechanism), 34 ... ECU (power transmission control means)

Claims (10)

Power that can transmit engine power and power of a first motor generator (hereinafter referred to as “first MG”) and a second motor generator (hereinafter referred to as “second MG”) to the vehicle axle. In a control device for a vehicle drive system provided with a transmission device,
The power transmission device receives an engine input shaft that transmits the power of the engine, a motor input shaft that transmits the power of the first MG, and the power of the second MG and transmits the power to the axle. An output shaft for outputting power for the engine, an engine side gear mechanism for transmitting the power of the engine input shaft to the output shaft without passing through the motor input shaft, and the power of the motor input shaft for the engine input shaft A motor-side gear mechanism for transmitting to the output shaft without going through, a first clutch for intermittently transmitting power between the engine input shaft and the motor input shaft, the motor-side gear mechanism and the output A second clutch that interrupts power transmission between the shaft and a third clutch that interrupts power transmission between the engine-side gear mechanism and the output shaft;
A control device for a vehicle drive system, comprising power transmission control means for determining an on / off state of each clutch and a required torque of each MG according to a rotational speed of the axle.   The control device for a vehicle drive system according to claim 1, wherein the power transmission control means sets the required torque of the engine to a constant value during operation of the engine.   The power transmission control means connects the first clutch and disconnects the second and third clutches when the rotational speed of the axle is equal to or lower than a predetermined first rotational speed. The control device for a vehicle drive system according to claim 2.   The power transmission control means sets the required torque of the first MG to the same value as the required torque of the engine and sets the required torque of the second MG based on the required torque of the output shaft. The control device for a vehicle drive system according to claim 3, wherein:   The power transmission control means includes the engine side gear mechanism and the motor side gear mechanism when the rotational speed of the axle is higher than a predetermined first rotational speed and equal to or lower than a predetermined second rotational speed. 5. The vehicle drive system according to claim 2, wherein each of the clutches is controlled so that the power of the engine is transmitted to the output shaft via a gear mechanism having a larger gear ratio. Control device.   When the rotational speed of the axle is higher than a predetermined second rotational speed, the power transmission control means passes through a gear mechanism having a smaller gear ratio between the engine side gear mechanism and the motor side gear mechanism. 6. The vehicle drive system control device according to claim 2, wherein the clutches are controlled to transmit the power of the engine to the output shaft.   The power transmission control means determines the required power of the MG based on the target power of the engine determined from the gear ratio of the gear mechanism that transmits the power of the engine to the output shaft and the required power of the output shaft. The vehicle drive system control device according to claim 5, wherein the control device is calculated.   The power transmission control means disconnects the first and third clutches and connects the second clutch while the operation of the engine is stopped. Control device for vehicle drive system.   9. The vehicle drive system control device according to claim 8, wherein the power transmission control means sets the required power of the MG to the same value as the required power of the output shaft.   The power transmission control means stores in advance a map of optimum operating points at which the total loss of the MG is minimized, and uses the map to determine the required torque of the first MG based on the required power of the MG. The control device for a vehicle drive system according to claim 7 or 9, wherein a required torque of the second MG is calculated.

Images